1. Field of the Invention
The present invention is related to an image signal generating apparatus operable to generate an image signal on the basis of a pulse signal issued in response to sliding operation performed by an operator.
2. Description of the Related Art
Jpn. unexamined patent publication No. 09-212162 discloses an electric string instrument. The electric string instrument comprises a main body provided with a reflective photo interrupter and a bow having a thin reflective member which reflects light. The bow is formed with a black pattern in the side surface thereof. Rectangular black areas are arranged at an equal interval in order to form this black pattern. Each rectangular black area is a light absorption area. Therefore, when sliding operation is performed with the bow, the black pattern of the bow absorbs light emitted from the photo interrupter, and other part reflects light emitted from the photo interrupter. Consequently, a pulse signal of a cycle corresponding to sliding velocity is input to a microcomputer in the main body from the photo interrupter. The microcomputer performs sound volume control in accordance with the cycle of the pulse signal. As just described, the electric string instrument is an apparatus to play music.